The quiet truth behind the inescapable headlines about man’s inhumanity to man is that the world is actually becoming a more peaceful place. Deaths from war and conflict have been declining for decades – and, if current trends continue, we can make them rarer still.

What mysterious force is sowing peace among humankind? One possible reason is that there are more atheists and nonbelievers than ever before.

A Pew poll from 2009, well before the Senate released its devastating torture report last month, asked whether torturing suspected terrorists could be justified found that the non-religious were most opposed to torture, with a combined 55% saying that it could rarely or never be justified. Gallup has also found that people with no religious preference are less supportive of the death penalty than any group of Christians. The non-religious are also among the most likely to say the invasion of Iraq was a mistake. The religiously unaffiliated are also less likely than Christians to believe that the US is superior to all other countries in the world, a hyper-patriotic attitude that’s hardly conducive to careful reflection about the use of American military power.

Religion’s violent tendencies also tend to be reflected in its adherents’ personal lives. The social scientists Christopher Ellison and Darren Sherkat found that conservative Protestants disproportionately support the use of corporal punishment, such as spanking or whipping, for children. The researchers speculate that this stems from theology: Christians who promote a literal interpretation of the Bible tend to believe that human nature is inherently evil, and that sin demands severe punishment. What’s more, the Bible itself (among its many other bloody verses) specifically calls for beating children in verses such as Proverbs 13:24. (By contrast, freethinkers like the famous American orator Robert Ingersoll recognized the cruelty of corporal punishment as early as 1877.)

As long as humanity was in thrall to the violent morality of religious texts, our societies were warlike and cruel. As the American revolutionary Thomas Paine said, belief in a cruel god makes a cruel man. It’s only in the last few decades, as we’ve begun to cast these beliefs off, that we’re making real moral progress.

The influence of the non-religious shows is also evident on an international scale. The nonprofit group Vision of Humanity publishes an annual Global Peace Index, which ranks countries on a broad spectrum of indicators, including violent crime, incarceration rates, weapon ownership, and military spending. Sociologist Phil Zuckerman summarizes their results in his new book Living the Secular Life:

...according to their most recent rankings, among the top ten most peaceful nations on earth, all are among the least God-believing – in fact, eight of the ten are specifically among the least theistic nations on earth. Conversely, of the bottom ten – the least peaceful nations – most of them are extremely religious.

Of course, not every atheist is peaceful and not every religious person is violent. Avowedly pacifist faiths like the Quakers or Unitarian Universalists have played an important role in peace movements and, in the other direction, there are lamentably prominent atheists like Sam Harris or the late Christopher Hitchens who’ve been entirely too cavalier about imperialism and military aggression. But in general, the trend is that, as the world becomes less religious, we can expect it to become even more peaceful.